Hydraulic system in a boat hull, preferably a boat hull having an outboard drive

ABSTRACT

An hydraulic installation in a boat hull for swinging a properller rig pivotably suspended in a shell on a boat transom using a piston-cylinder device arranged in a hydraulic control circuit. A control valve included in the hydraulic circuit for controlling the flow to and from the hydraulic cylinder is sealingly mounted in a through-opening in the shell, so that one side of the valve faces outwardly towards the propeller rig in order to be subjected to water spray during driving and serve as an oil cooler.

CROSS REFERENCE TO RELATED APPLICATION

This is the 35 USC 371 national stage of international applicationPCT/SE99/02195 filed on Nov. 25, 1999, which designated the UnitedStates of America.

BACKGROUND OF THE INVENTION

The present invention relates to a hydraulic installation in a boathull, comprising a hydraulic circuit with pump means, pressuremedium-actuated operating means, control valve means for controlling theflow between the pump means and the pressure-actuated operating means,and cooling means for cooling the pressure medium in the hydrauliccircuit

The invention also relates to a boat propeller drive, comprising a shellintended to be permanently mounted against a boat transom, a propellerrig mounted in the shell for pivoting about a steering axis, at leastone pressure medium-actuated piston-cylinder device, by means of whichthe propeller rig is pivotable about the steering axis, and a controlvalve for controlling the pressure medium flow to and from the cylinderof the piston-cylinder device.

In most hydraulic installations of the type described above, some formof cooling arrangement is required to prevent overheating of thepressure medium. Usually, a separate heat exchanger is used in thehydraulic circuit. The purpose of the present invention is, in ahydraulic installation of the type described by way of introduction, tomake it possible to achieve satisfactory cooling of the pressure mediumwithout using a separate heat exchanger only intended for coolingpurposes.

SUMMARY OF THE INVENTION

This is achieved according to the invention by virtue of the fact thatthe control valve means comprise at least one control valve with a valvehousing, which is so fixed relative to the boat hull, that at least aportion of the valve housing is exposed to the hull surroundings, tothereby serve as cooling means for the pressure medium in the hydrauliccircuit.

By placing the valve housing so that its outside is subjected to waterspray during driving, it can assume the function of a conventionalseparate cooler, meaning that a separate cooler can be eliminatedwithout having to add a new component to the hydraulic circuit.

In a boat propeller drive of the above described type, particularadvantages are achieved if the control valve has a valve housing whichis so arranged on the shell that at least a portion of the valve housingis exposed towards the propeller rig.

The control valve can then be delivered as a portion integrated into thepropeller drive with pre-installed hydraulic lines between the valve andthe steering cylinder(s) of the rig. No after-mounting of the controlvalve is required, and by virtue of the fact that the valve is exposedtowards the propeller rig, it will automatically be subjected to waterspray when the boat is driven. In a preferred embodiment of thepropeller drive according to the invention, the valve housing issealingly fixed in a through-opening in the shell. In this case it issufficient to connect the lines from the inboard-mounted pump devices tothe valve housing connections on the inside of the shell. No lines needbe drawn through the shell or the transom of the hull.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail with reference toexamples shown in the accompanying drawings, where

FIG. 1 shows a schematic side view of a boat propeller drive,

FIG. 2 shows schematically one embodiment of a hydraulic steering systemfor the boat propeller drive in FIG. 1,

FIG. 3 shows a diagram of a second embodiment of a hydraulic steeringsystem, and

FIG. 4 shows a diagram of a third embodiment of a hydraulic steeringsystem.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an inboard/outboard drive 1 of Aquamatic® type, comprisinga carrier or shell. 2, intended to be fixed to the transom and sealagainst the edges of an opening of the transom. The drive 1 has a rigleg 3, which is pivotally suspended in a fork-like carrying element 4via a shaft 5, the center axis 6 of which forms the steering axis of thedrive. The fork element 4 is journalled at its upper end in the shell 2for pivoting about a horizontal axis 7. At its lower end, the forkelement 4 engages a pair of piston-cylinder devices 8 arrangedsymmetrically about the shaft 5, only one of which being shown in thefigure. In the example shown, the piston rod 9 of the respective device8 is pivotally joined to the element 4 via a pin 10 in a bore 11 in therespective fork leg of the element 4, while each respective hydrauliccylinder 12 is pivotally mounted in the shell 2 via a pin 13. The pistoncylinder devices 8 form so-called trim- and tilt-cylinders, by means ofwhich the angle of the rig leg 3 can be trimmed during operation and bymeans of the rig leg can be swung up out of the water when at rest.

Two hydraulic piston cylinder devices 20 a and 20 b orientedsymmetrically relative to the longitudinal plane of symmetry of thedrive, are pivotally joined to the lower end of each leg 21 of the forkelement 4 and the cavitation plate 22 of the drive. In the exampleshown, the cylinder 23 of the respective piston cylinder device 20 isjoined to the respective fork leg 21 by means of a pin 24 while therespective piston rod 25 is joined to a mounting 26 on the cavitationplate via a pin 27.

The schematic drawing in FIG. 2 shows in cross-section a portion of atransom 30, where 31 designates its inside, 32 its outside and 33 athrough-opening, against the edges 34 of which the shell 2 is sealinglyfixed. In an opening 35 in the shell 2, a control valve 36 is sealinglyfixed against the edges of the opening 35. The valve 36 communicates vialines 37 and 38 with a hydraulic pump 39 which is connected to a manualdrive means (not shown in more detail here), e.g. a steering wheel,which, when turned, pumps hydraulic oil both to the control valve 36 andto and from cylinder chambers in the cylinders 20 a and 20 b, as will bedescribed in more detail below with reference to FIGS. 3 and 4. Thecontrol valve 36 is also connected to a pressure line 40 from ahydraulic pump 41 driven by a drive motor (not shown) and via a line 42to an oil reservoir 43, to which a suction line 44 to the pump 41 isconnected. Via the control valve and the hydraulic lines 45, 46, oil canbe pumped to and from cylinder chambers in the cylinders 20 a, 20 b. Thevalve can be of the type shown and described in our parallel patentapplication No. 9804073-6.

By virtue of the fact that the control valve 36 is mounted in an openingin the shell 2, so that its outside is subjected to water spray, it canserve as an oil cooler for the hydraulic oil in the system and thus, atleast in certain installations, completely replace a separate oilcooler. In order to increase the cooling capacity of the control valve36, it can, as shown in FIG. 3, be provided with cooling flanges 80 or,as shown in FIG. 4, be made with a channel 81, which extends through thehousing 50 and at each end has connections 82 for coolant hoses 83 tothe engine coolant. Possibly, the channel 81 can also be provided withcooling flanges 84.

The hydraulic installation according to the invention has been describedabove with reference to one embodiment in which the pressuremedium-actuated operating means are steering cylinders in a hydraulicservo system, but the invention is of course not limited to servosteering systems. It can also be applied in hydraulic systems forcontrolling the flow, for example to trim cylinders for propeller driveunits and trim planes.

What is claimed is:
 1. Hydraulic installation in a boat hull, comprisinga hydraulic circuit (37,38,45,46) with pump means (39,41), pressuremedium-actuated operating means (20 a,20 b), control valve means (36)for controlling the flow between the pump means and thepressure-actuated operating means, and cooling means for cooling thepressure medium in the hydraulic circuit, characterized in that the pumpmeans are located inside the hull and that the control valve meanscomprise at least one control valve (36) with a valve housing, which isso fixed relative to the boat hull, that at least a portion of the valvehousing is exposed to the hull surroundings, to thereby serve as coolingmeans for the pressure medium in the hydraulic circuit.
 2. Installationaccording to claim 1, characterized in that the valve housing, at leaston the side exposed to the hull surroundings, is provided with coolingflanges (80).
 3. Installation according to claim 1, characterized inthat the valve housing is made with a through-channel (81), which has aninlet and an outlet (82) for connection to a coolant line (83). 4.Installation according to claim 3, characterized in that the inner wallof the channel (81) is provided with cooling flanges (84). 5.Installation according to claim 1 in a boat hull, which has a propellerdrive (1) comprising a carrier (2) permanently mounted on the hulltransom (30), and a propeller rig (3) mounted in the carrier forpivoting about a steering axis (6), the pressure medium-actuatedoperating means (20 a,20 b) being active to pivot the propeller rigabout the steering axis, characterized in that the valve housing iscarried by the carrier (2).
 6. Installation according to claim 5,characterized in that the carrier is a shell (2) mounted against anopening in the transom (30), said shell having a through-opening (35),in which the valve housing is sealingly fixed.
 7. A boat propellerdrive, comprising: a shell intended to be permanently mounted against aboat transom; a propeller rig which is mounted in the shell for pivotingabout a steering axis; at least one pressure medium-actuatedpiston-cylinder device, by means of which the propeller rig is pivotableabout the steering axis; a control valve for controlling the flow ofpressure medium to and from the cylinder of the piston-cylinder device;and a pump means for pumping the pressure medium mounted inside the boattransom, wherein the control valve has a valve housing, which is socarried by the shell, that at least a portion of the valve housing isexposed towards the propeller rig.
 8. Boat propeller drive according toclaim 7, characterized in that the valve housing is sealingly fixed in atrough-opening (35) in the shell (2).